Grinder with oscillating head



Feb. 14, 1961 M. M. BASS ETAL GRINDER WITH OSCILLATING HEAD OriginalFiled March 29, 1956 5 Sheets-Sheet 1 INVENTOR. MILES M 81458 RAMsAr Man: y a: c. HAMMOND PHIl/F J: ROBIJCHUNG ATTORNEYS Feb. 14, 1961 M. M.BASS ETAL 2,971,296

GRINDER WITH OSCILLATING HEAD Original Filed March 29, 1956 5Sheets-Sheet 2 Z Y INVENTOR. MILEJM. ans:

5 RAMS/1V M azu ATTORNEYS M. M. BASS ETAL GRINDER WITH OSCILLATING HEADOriginal Filed March 29, 1956 Feb. 14, 1961 5 Sheets-Sheet 3 a N m w Y 5NC V. NSr MO- B ME W5 N a M o R I.,MAR Q bw M m A s r MM W 5 2 2 MHMP fv 3 M U 2 2 Feb. 14, 1961 5 Sheets-Sheet 4 INVENYOR. MILES BASS mmsnr M.8541. y 1:! c. HAMMOND PHIL/P J: ROB/SCHUNQ ATTORNEYS Feb. 14, 1961 M.M. BASS ETAL 2,971,296

GRINDER WITH OSCILLATING HEAD Original Filed March 29, 1956 5Sheets-Sheet 5 m 50 L\\ \\\Y] L\ i/ Z ll lllu us \\\\\jT \\\\1\\ I23 3436 T Q 6 I35 133 '25 I22 {I28 25 I ii X IIQ 2 l 1 I34 m m '24 T 29 I3]I26 INVENTORL M1155 M. ans:

7 RAMJAY M. 8:11 vBY LEE 6. HAMMOND g PHILIP J. nos/Hume TTORNEYS UnitedStates Patent GRINDER WITH OSCILLATING HEAD now Patent No. 2,922,258,dated Jan. 26, 1960. Di-

vided and this application May 11, 1959, Ser. No. 812,449

9 Claims. (CI. 51-55) This invention relates to a grinderandparticularly to one in which the grinding wheel may be caused tooscillate at a controllable frequency and amplitude. This is a divisionof our application Serial No. 574,728, filed March 29, 1956, now PatentNo. 2,922,258, granted lanuary 26, 1960.

In conventional tool grinding equipment, it is customary to provide arotatable grinding wheel adjacent a work supporting table. The table isnormally movable for adjustment relative to the axis of the grindingwheel, so that the plane defined by the working surface of the wheel andthe plane defined by the table top will intersect at whatever angle isdesired to facilitate grinding the work in a desired manner. However, inall of these grinders, insofar as we are aware, it is necessary for theworkman who is utilizing the machine, such as for grinding a tool point,to manually move the tool point across the working face of the grindingwheel. The reasons for such movement of the tool point across the faceof the grinding wheel are well known to the industry and may besummarized here by pointing out that such movement of the tool tendsboth to speed the grinding operation and to work out any irregularitieswhichmay exist in the face of the grinding wheel, i.e., dress the wheel.This latter tends to secure a more nearly flat and a more smoothlyground surface than would be possible if no such movement of the toolpoint were employed. Further, this movement of the tool point effects adesirable amount of socalled cross-grain grinding and prevents the wheelgrit from channeling the work.

This movement, while universally practiced where tool points andgrinders are used, is nevertheless tedious, time consuming and tiring tothe workman. Also, it is difficult to grind a tool accurately whilemanually moving it along a table and with respect to a grinding surface.Further, where the tool is moved relative to the table, the tablebecomes worn, and such wear is often sufi'lcient to alter the positionalrelationship between a tool being held on the table and the wheel.

These disadvantages of the technique previously employed have long beenrecognized, but no acceptable provision for solving them has, insofar aswe are aware, been offered to the industry. It is recognized that somemachines have been provided which hold the tool mechanically and providea relative oscillation between the wheel and the tool, but thesemachines are relatively expensive, are often difiicult to utilize, andtheir use is limited to conditions involving high production operation.

It is therefore desirable to provide a tool grinding machine adaptableto general use, by which a workman can maintain all of the precision andindividual attention to the exact shaping to the tool point, which iscustomarily obtained where the tool point is guided by hand, whileavoiding the fatigue, inconvenience and occasional inaccuracy whichsometimes occur where the relative motion of the tool with respect tothe axis of the grinding 2,971,296 Patented Feb. 14, 1961 wheel isprovided by manually moving the tool across the face of the grindingwheel.

Accordingly, a principal object of the invention has been the provisionof a grinding machine effective for obtaining the individual shaping ofthe work, such as a tool point, which is customarily obtainable by handguiding of said work with respect to the grinding surface, whileeliminating the fatigue, inaccuracy and inconvenience of manually movingthe work back and forth across the face of the grinding wheel.

A further object of the invention has been to provide a machine, asaforesaid, in which the workman can hold the work, especially a toolpoint, stationary with respect to a supporting table, either with orwithout assistance of a mechanical holder or guide, and the relativemotion of the work with respect to the axis of the grinding wheel isprovided by the machine.

A further object of the invention has been to provide a machine, asaforesaid, having a device by which the axis of the grinding wheel iscaused to oscillate with respect to the work supporting table.

A further object of the invention has been to provide a device, asaforesaid, in which either or both the frequency and amplitude of saidoscillations are individually controllable.

A further object of the invention has been to provide a machine, asaforesaid, in which the preceding named objectives may be accomplishedwhile retaining the previously convent onal practice of adjusting thetable to change the angle between the plane of the grinding face of thewheel and the plane of the work supporting surface of the table.

A further object of the invention has been to provide a device, asaforesaid, by which the foregoing named objectives may be accomplishedin a machine capable of relatively general use.

A further object of the invention has been to provide a machine, asaforesaid, in which the several adjustments above mentioned may be madesimply, accurately, and while the machine is in motion, and wherein themachine will remain in an adjusted condition reliably through anyordinary term of use.

A further object of the invention has been to provide a device, asaforesaid, which will be adaptable to use with many types of grindingwheels, but which will be specifically adapted to use with diamondfilled grinding wheels.

A further object of the invention has been to provide a device, asaforesaid, which will also be adapted to use with grinding wheelsemploying a technique commonly identified as electrolytic grinding.

A further object of the invention has been to provide a device, asaforesaid, which will eliminate the inaccuracies resulting from wear ofthe table surface, which now sometimes occurs where the tool is movedalong, and with respect to, the surface of the table.

A further object of the invention has been to provide a machine, asaforesaid, which can be employed by any ordinarily skilled personnelwithout requiring the use of techniques different from those which arealready familiar.

A further object of the invention has been to provide a device, asaforesaid having a wheel supporting spindle which is adaptable forconversion Without major change therein to double-end operation, wherebya second Wheel and table arrangement may be provided adjacent to theopposite end of the spindle supporting the first named wheel.

A further object of the invention has been to provide a machine, asaforesaid, which will be adaptable for grinding tools of a variety ofshapes.

Other objects and purposes of the invention will be apparent to personsacquainted with equipment of this general type upon reading thefollowing disclosure and inspecting the accompanying drawings,

In the drawings:

Figure 1 is a side elevational View of the machine to which thisinvention relates, with the adjacent side sheets thereof broken away.

Figure 2 is a sectional view taken on the line IIII of Figure 1.

Figure 3 is a sectional view taken on the line Ill-J11 of Figure l. V

' Figure 4'is a sectional view taken on the line IV--IV of Figure 3.

, Figure 5 is a sectional view taken on the line VV of Figure 1.

Figure 6 is a sectional view taken on the line VIVI of Figure 3.

Figure 7 is a sectional view taken on the line VIIVII of Figure 6.

For the purpose of convenience in description, the terms upper, lower,left, right, and derivatives thereof, will have reference to the machineand parts thereof as appearing in Figure 2. The terms front and rearwill have reference to the left and right sides, respectively, of themachine as appearing in Figure 1. The terms inner, outer, andderivatives thereof, will have reference to the geometric center of saidmachine and parts thereof.

GENERAL DESCRIPTION In meeting the objects and purposes above set forth,we have provided a machine having an adjustable, but relativelystationary, table with which a manually operable tool holder may beused, if desired, said machine having a structure for supporting arotatable grinding wheel adjacent to said table. The grinding wheel ismounted for oscillatory movement transversely of its rotational axis.During such movement, the center of said Wheel traces an arcuate pathwhich is generally parallel to the surface of the grinding table, thatis, the tangent at the midpoint of said path is parallel both to thesurface, and to an adjacent edge 5d, of said table. This result isobtained by securing the grinding wheel 11 (Figures 1 and 4) to a shaft12, which is rotatably mounted adjacent to the table 14 upon a shaftsupport bracket 13. The support bracket 13 is in turn pivotallysupported by the bearing assembly upon the platform 15 of the machineframe 11). The shaft 12 is continuously rotated by a belt 16 driven bythe motor 17.

Oscillation of the bracket 13 about its pivotal support 29 is, in thepreferred embodiment here shown, effected by a lever 18 (Figures 2 and5) pivotally supported by the pillow block 19 on the upper wall 34 offrame 10 and connected to the bracket 13 by the pitman 21. The lower endof the lever 13 is caused to oscillate, or is alternatively held againstoscillation, by a roller 22, which is mounted upon the shaft 26,rotatable at a con trollable speed with the pulley 25. The shaft 26 maybe moved radially of the axis of the pulley by a hand wheel 23 workingthrough a mechanism 24 for adjusting the amount of eccentricity of theshaft 26 with respect to said pulley. The amplitude of oscillation ofsaid wheel 11 is, therefore, controlled by the eccentricity, if any, ofthe roller 22 with respect to said pulley 25. Rotation of said pulley 25is secured through the belt 27 driven through a suitable speed reducer28 from, and by, the motor 29. The speed of such oscillation is adjustedthrough the speed reducer 23 in response to adjustment of the hand wheel31.

DETAILED CONSTRUCTION A. Frame and table 7 As shown particularly inFigures 1 and 2, the base frame 10 of the grinding machine to which thisinvention relates is upright, substantially rectangular, in thisparticular embodiment, and fabricated from any sturdy, conventionalmaterial, such as steel plates. A platform or bed plate 15 is mountedupon the upper. wall 34 of the frame 19 and extends forwardly of thefront wall 123 of the machine frame 10. The forward end of the platform15 is provided with ways 35 on its upper surface, which engage andslidably support the base 36 of the table 14 for slidable, adjustablemovement rearwardly and forwardly of the machine frame. 10. Suchmovement is obtained by means of the threaded engagement between thescrew 37 (Figures 3 and 4) and the double or split nut 38, which hasfront and rear portions 40 and 41, respectively, through both of whichthe screw 37 is threadedly received. One portion, here the rear portion41, is rigidly secured to the platform 15 between the ways 35. The screw37 is rotatably supported upon the front end of the table base 36 andheld against axial movement with respect thereto in a substantiallyconventional manner. A hand Wheel 45 is secured to the front end of thescrew 37 for effecting rotation threreof, hence movement of the base 36along the ways 35.

The table base 36 (Figures 3 and 4) extends laterally of, and above, theways 35 and supports the bottom of a hood 46, which substantiallysurrounds the table 14 and the grinding wheel 11. Left and right tablesupport members 47 and 48 (Figures 6 and 1) are mounted upon, and extendupwardly from, the table base 36 adjacent to its lateral edges (Figure3) within the hood 46. The members 47 and 48 are preferably hollow andhave concave, arcuate upper surfaces 4? having a substantiallyhorizontal common axis 50 (Figures 4 and 6) lying within the planedefined by the upper surface 51 of the table 14. A pair of tablebrackets 52 and 53 (Figure 5) are secured to, and depend from, the lowersurface of the table 14 near its lateral edges. Said brackets 52 and 53have arcuate, convex lower surfaces 54 (Figure '6), which are snugly,slidably and respectively receivable into the upper, concave surfaces49. Side plates 55 are secured to, and extend downwardlybeyond, thelateral sides of the brackets 52 and 53. Said side plates 55 embrace thelateral sides of the support members 47 and 48 when they are engaged bythe brackets 52 and 53, respectively, in order to prevent dirt fromentering between the brackets and their corresponding support members.The brackets 52 and 53 are slidable with respect to the support members47 and 48 for effect The bearing assembly 26, which pivotally supportsthe support bracket 13 (Figuresl and 4) includes a pivot shaft 82, whichis substantially parallel with the extended axis of the screw 37 and issecured at its opposite ends in the blocks 83 and 84 (Figure 1) mountedupon the rearward end of the platform 15. The shaft 82 is preferablylocated substantially directly behind the center line of the. table base36. The support bracket 13 (Figure 4) includes a cylindrical housing 35at its lower end, which encircles the pivot shaft 82 and is rotatablymounted upon said shaft by means of the bearings 86. Said bracket 13also includes a support plate 87, which is secured to, and spaced from,the housing 35 by a pair of webs 88'. The shaft housing 89, in which thegrinder shaft 12 is rotatably supported by means of the bearings 91, ismounted upon the plate 87. The grinder shaft 12 is axially parallel withthe pivot shaft 821. and extends both forwardly and rearwardly fromwithin the shaft housing 89.

A grinding wheel mount 92 (Figure 4) is rigidly secured to the frontextension 93 of the shaft 12 by means of a bolt 94 in a substantiallyconventional manner..

The rearward face of the wheel mount 92 and the forward annular end wall95 of the shaft housing 89 are provided with a suitable sealing devicefor preventing the Waste materials of the grinding operation fromgetting'into the bearings 91. The grinding wheel 11 is secured to thefront surface of the wheel mount 92, as by means of bolts 96 (Figure 4),so that the planar grinding face of said wheel 11 lies in asubstantially vertical plane and said Wheel can be disposed adjacent to,and parallel with, the edge 78a (Figure 5) of the table 14 within therecess 78.

The support bracket 13 and that portion of the shaft 12 and the shafthousing 89 disposed outside of the hood 46 are substantially enclosed byan enclosure 97 (Figure 4), which is mounted upon the frame and has anopening 93 in its front wall, through which said shaft housing 89extends. The opening 98'is laterally elongated to permit oscillation ofsaid housing 89 with respect to the enclosure 97. The space between thehousing 89 and the enclosure 97 is closed by an annular sheet 99 havinga flanged, internal edge 99a, which snugly embraces the housing 89. Saidflanged edge 99a, hence the sheet 99, is secured to the housing 89 by aresilient ring 81 and said sheet 99 slida-bly and snugly engages thefront wall of the enclosure 97 to provide a dust seal.

C. Wheel drive mechanism The rear extension 106 of the shaft 12 supportsa pulley 1117 (Figures 1 and 4), which is connected to a pulley 108 bythe belt 16, said pulley 108 being mounted upon the shaft of the motor17. The motor 17 is supported below the platform 15, in this particularembodiment, upon a motor mount 169 so that the axis of said motor isparallel with the shaft 12 (Figure 2). The motor mount 1119 is pivotallysupported along one edge thereof, parallel with said motor axis, upon apivot shaft 111, which is supported upon the frame 10. An arm 112extends from the opposite edge of said motor mount 1G9 and supports asubstantially horizontal pin 113 near its free end, which pin slidablyextends through a lengthwise slot 114 in the support bar 115 near thelower end thereof. The upper end of said bar 115 (Figures 1 and 2 ispivotally mounted upon the upper wall 34 of the machine frame 10.

D. Oscillatory drive mechanism The pitman 21 is pivotally supported atone end upon the front web 88 between the support plate 87 and thecylindrical housing 85. The other end of said pitman 21 is pivotallysecured to the upper end of the lever 18, which lever is pivotallysupported between its upper and lower ends by a pivot shaft 116 and apillow block 19 mounted upon the top wall 34 adjacent to the bearingassembly 211. The lower end of the lever 18 is provided with a slot 118which is elongated lengthwise of said lever 18. The roller 22 (Figures5, 6 and 7) is rotatably disposed within the slot 118 and is engageablewith the side walls of said slot. The shaft 26 is rigidly secured to anadjustment block 119 (Figure 7), which is part of the adjustmentmechanism 24 for effecting movement of the roller 22 into and out of aposition of concentricity with the pulley 25.

The adjustment mechanism 24 (Figures 6 and 7) is comprised of an outercylindrical housing 122, which is supported upon the front wall 123 ofthe machine frame 11) and rotatably supports an inner, cylindricalhousing 124 by means of the bearings 125. Said inner and outer housingsare concentric and their common axis is preferably parallel with thepivot shaft 82 (Figure 4). The inner housing 124 (Figure 7) extendsslightly rearwardly of the outer housing 122 to mount the pulley 25. Apair of spaced, transverse, substantially parallel slide rods 12-6 and127 extend diametrically through, and are secured to, the inner housing124. Said rods 126 and 127 slidably support the adjustment block 119within the yoke 133 and with respect to the inner housing 124 formovement in a direction parallel with said slide rods. Said adjustmentblock 119 is provided with an elongated opening 128, which is axiallytransverse of the slide rods 126 and 127 and radially elongated in adirection which, if projected, would intersect said rods 126 and 127 atan acute angle, such as approximately 60 (Figure 6). An adjustment rod129 extends through the opening 128 and is engaged at its opposite endsby the arms 131 and 132 of the yoke 133, which embraces the oppositesides of the adjustment block 119. The yoke 13 3 is movable within, andlengthwise of, the inner housing 124, whereas the adjustment block 119is movable transversely of said inner housing 124, but not lengthwisethereof. Thus, when the yoke 133 is moved lengthwise of said innerhousing 124-, such movement will be translated into transverse movementof the adjustment block 119 as a result of the cam action of the wallsof the elongated opening 128 upon the adjustment rod 129, depending uponthe direction of movement of said yoke 133.

The front end of the yoke 133 (Figures 6 and 7) rotatably supports therearward end of an adjustment screw 134, which is co-axial with, andextends into, the inner housing 124. Said screw 134 extends forwardlythrough, is threadedly engaged by, and is supported upon, a hub 135(Figure 1), which hub is supported. upon the front wall 123 of the frame14 The hand wheel 23, for effecting rotation of the screw 134, ismounted on the front end of said screw 134. Thus, by appropriaterotation of the wheel 23, the roller 22 is caused by the adjustmentmechanism 24 to move into and/ or out of a position of concentn'citywith the pulley 25.

The pulley 25 is connected by the belt 27, in a substantiallyconventional manner, to the output of the speed reducer 23, which iscontrolled by the hand wheel 31 mounted thereon, and which is connectedto the motor 29, also in a substantially conventional manner.

OPERATION Prior to operating the grinding machine to which thisinvention relates, certain adjustments may be required in order toproperly prepare said machine for said operation. Having selected agrinding wheel 11 having the proper type of grinding face 194, saidwheel is mounted upon the wheel mount 92 (Figure 4) by the bolts 96.During the securing of said wheel 11 on the mount 92, it may beadvantageous to move the table 14 forwardly, away from the wheel mount92. This is accomplished by turning the hand wheel 45 in the properdirection, whereby the table base 36 will be moved along the ways 35 bythe operation of the screw 37 and the split nut 38 in a manner whichwill be apparent.

When the proper adjustment of the table has been obtained, the motor 17(Figure 1) can then be energized, thereby causing the shaft 12 andgrinding wheel 11 to rotate. The motor 29 is also energized, whichdrives the speed reducer 28, which in turn rotates the pulley 25 of theadjustment mechanism 24. The pulley 25, acting through the inner housing124 (Figure 6) and the adjustment block 119, causes the shaft 26, hencethe roller 22, to rotate about the axis of the inner housing 124.

If the axis of the roller 22 (Figures 6 and 7) is eccentric with respectto the axis of the pulley 25, rotation of the pulley 25 will effect areciprocable pivoting of the lever 18 about the pivotal axis provided bythe lever bearing 19. Such reciprocation will be transmitted by thepitman 21 (Figure 2) to the support bracket 13 for effecting acorresponding pivotal reciprocation of said support bracket about thepivotal axis thereof provided by the bearing assembly 20. This willcause the shaft 12 to oscillate through a relatively small arc crosswiseof the machine, the tangent of said are at its midpoint beingsubstantially parallel to the pivot axis 511 of the table 14, andthereby effect a similar laternal oscillation of the grinding wheel 11.Where the grinding wheel, as shown here, has a relatively narrowgrinding face 104, the oscillation of the grinding wheel will berelatively small and,

as a general rule, will be somewhat less than'the'radial width of thegrinding face on said wheel 11. Thus, the path traversed by the axis ofthe shaft 12 during said oscillations, although arcuate, will berelatively fiat and substantially parallel to pivot axis 50 or" thetable 14. However, since the path of oscillation of said shaft 12 isarcuate, and since the radius of this are is substantially less than,here approximately one-half of, the axial distance between the shaft 1'2and the shaft of the driving motor 17, some provision must be made forkeeping the belt 16 under uniform tension during the operation. This isaccomplished by pivotally supporting the motor mount 109 upon the pivotshaft 11.1 so that said motor partially hangs upon the belt 16. Thus, asthe shaft 12 moves upwardly and downwardly a relatively small distanceduring the arcuate movement thereof, the motor 17 is free to moveupwardly and downwardly this same slight distance.

The [flexible and resilient annular sealing sheet 9% (Figure 4) permitsmovement of the shaft housing 89 with respect to the enclosure 97 duringthe oscillation of said shaft housing 39 without impairing the sealprovided thereby. The opening 98 in the enclosure Q7, through which theshaft housing 89 extends, is sufficiently large to permit the desiredoscillation of the shaft housing 89.

Adjustment of the oscillation distance or amplitude of the shaft 12 iseffected by turning the hand wheel 23 associated with the adjustmentmechanism 24. As shown in Figures 6 and 7, turning of the hand wheel 23effects either a forward or rearward movement of the yoke 133, wherebythe adjustment block 119, which supports the shaft 26, is moved in adirection transversely of the axis of the inner housing 124. Thismovement of the block 119 produces a corresponding radial movement ofthe roller 22, thereby causing or changing the eccentricity in the axisof the roller 22 with respect to the inner housing 124. By appropriateadjustment of the hand wheel 23, the roller 22 can be caused to becompletely concentric with the pulley 25, whereby the grinding wheel illcan be caused to rotate without any reciprocation or oscillationwhatsoever.

It will be recognized that the adjustment of the table E4, theadjustment mechanism 24 and the speed reducer 2 8 can be effected whilethe machine is in operation.

The necessary adjustments having thus been completed, the tool, as shownat 137 in Figure 4 is placed upon the table 14 and held there, eithermanually or by mechanical means, while the grinding wheel 11reciprocates with respect to the table 14.

Although particular, preferred embodiments of the invention have beendisclosed hereinabove for illustrative purposes, it will be understoodthat variations of modifications thereof, which do not depart from thescope of such disclosure, are fully contemplated unless specificallystated to the contrary in the appended claims.

What is claimed is:

1. In a grinding machine having a bracket supporting a grinding wheelfor rotation around a first axis and a frame supporting said bracket forpivotal movement around a second axis spaced from and parallel with saidfirst axis; an elongated pivot member pivotally supported upon saidframe for pivotal movement around a pivot axis near to and parallel Withsaid second axis; means connecting one end of said pivot member to saidbracket whereby pivotal movement of said pivot member effects pivotalmovement of said bracket; bearing means supported upon said frame nearsaid other end of said pivot member; a driven member supported withinsaid bearing means for rotation around a third axis parallel with saidsecond axis; a shaft having an axis parallel with said third axis, andpositioning means drivingly connected to said driven member and to saidshaft and supporting said shaft upon said driven member for. radialmovement into andv out of a position. coaxial means connected betweensaid driven member and said positioning means for effecting said radialmovement of said shaft. with respect to said third axis.

2. In a grinding machine having a bracket supporting a grinding wheelfor rotation around a first axis and a frame supporting said bracket forpivotal movement around a second axis spaced from and parallel with saidfirst axis; an elongated, substantially upright pivot member supportedat a point spaced from the ends thereof upon said frame for pivotalmovement around a pivot axis near to and parallel with said second axis;means connecting the upper end of the pivot member to said bracketwhereby pivotal movement of said pivot member elfects pivotal movementof said bracket; means defining a lengthwise slot in said pivot membernear the lower end thereof and opening in a direction parallel with saidsecond axis; a bearing structure supported upon said frame near saidlower. end of said pivot member; a driven member supported within saidbearing structure for rotation around a third axis parallel with saidsecond axis; positioning means supported within said driven member formovement in a direction substantially perpendicular to said third axis,said positioning means being drivingly connected to said driven memberfor rotation therewith; a shaft supported upon said positioning meansfor radial movement therewith toward and away from a position coaxialwith said third axis and also being drivingly connected thereto forrotation therewith; means on said shaft engageable with the walls ofsaid slot and movable lengthwise of said slot, whereby movement of theshaft axis around said third axis pivots said pivot member around saidpivot axis; and manually operable adjusting means mounted upon saidframe and engageable with said positioning means for efiecting saidradial movement of said shaft.

3. The structure of claim 2 wherein said driven member includes acylindrical sleeve coaxially and rotatably supported within said bearingstructure, and a pair of spaced parallel rods mounted upon and'withinsaid sleeve and intersecting perpendicularly the rotational axisthereof; wherein said positioning means includes a slide member slidablysupported upon said rods within said sleeve for movement perpendicularlyof said third axis, said slide member having an elongated cam slottherethrough, the sidewalls of said cam slot defining substantiallyparallel planes intersecting said rods and the third axis at acuteangles; and wherein said adjustment means includes a bifurcated memberhaving a pair of arms extending along opposite sides of said slidemember within said sleeve and supporting between said arms a rodextending through and slidably engaging said side walls of said camslot, and means engaged with said bifurcated member for effectingmovement thereof with respect to said sleeve in a direction parallelwith said third axis, whereby said slide member is moved lengthwise ofsaid parallel rods and radially within said sleeve.

4. In a grindingmachine having a bracket supporting a grinding wheel forrotation about a first axis and a frame supporting said bracket forpivotal movement around a second axis spaced from and parallel with saidfirst axis, an adjustable eccentric and means deriving oscillatorymotion from said eccentric and applying same to effect oscillatorymotion of said bracket, the improve ment in means adjusting the radiusof eccentricity of said eccentric which comprises bearingstructurernounted on said frame; a cylindrical sleeve coaxially androtatably supported within said bearing structure for rotation about athird axis parallel with said second axis; a pair of spaced parallelrods mounted upon and extending diametrically within said sleeve androtatable therewith; a slide member slidably supported upon said rodsWithin said sleeve for movement perpendicularly of said third axis, saidslide member having an elongated cam slot therethrough, the side wallsof said cam slot defining substantially parallel planes intersectingsaid rods and said third axis at acute angles; a bifurcated memberhaving a pair of arms extending along opposite sides of said slidemember within said sleeve and a rod supported between said arms andextending through and slidably engaging the side walls of said cam slot,rotatable threaded adjusting means rotatably attached to said bifurcatedmember for moving said bifurcated member axially with respect to saidbearing structure and said sleeve upon rotation of said adjusting meanswith respect to said hearing structure to thereby move said eccentricradially with respect to said sleeve.

5. In a grinding machine having a support bracket supporting a grindingwheel for rotation around a first axis and a frame supporting saidbracket for pivotal movement around a second axis spaced from andparallel with said first axis, an eccentric and means derivingoscillatory motion from said eccentric and applying oscillatory motionto said bracket; adjustable supporting and driving means for saideccentric arranged for permitting adjustment of the throw of saideccentric while same is in operation and for holding same in a preciselydeterminable adjusted position including bearing structure fixedlymounted on said frame; a cylindrical sleeve coaxially and rotatablysupported within said bearing structure for rotation about a third axisparallel with said second axis; a pair of spaced parallel rods mountedupon and extending diametrically within said sleeve; driving means onsaid sleeve for rotating same; a slide member slidably supported uponsaid rods and located within said sleeve and movable perpendicularlywith respect to said third axis, said slide member having an angularlypositioned cam surface thereon, said cam surface defining a planeintersecting said third axis at an actue angle, said eccentric beingmounted on said slide member and said slide member being drivinglyconnected to said sleeve so that said eccentric is rotated by saiddriving means about said third axis; a bifurcated member having a pairof arms extending along opposite sides of said slide member and locatedwithin said sleeve; a rod supported on and extending between said armsand slidably engaging said cam surface, adjusting means attached to saidslide member and manually operable means for moving said adjustablemeans axially with respect to said bearing structure and said sleeve andthereby effecting movement of said bifurcated member axially of saidsleeve and thereby moving said eccentric radial y with respect to. saidsleeve.

6. Mechanism for adjustably supporting the throw of an eccentric withrespect to an axis and arranged for adjustment of said throw while saideccentric is rotating around said axis and for holding same in adjustedposition after said adjustment is effected, comprising in combination:bearing structure and means for supporting same; a cylindrical sleeveconcentric with said axis and supported within said bearing structurefor rotation around said axis, a pair of spaced parallel rods mountedupon and extending diametrically within said sleeve; driving means forrotating said sleeve; a slide member slidably supported upon said rodsand located within said sleeve for movement radially with respectthereto, said slide member having an elongated cam slot therethrough,the side walls of said cam slot defining substantially parallel planesintersecting said rods and said axis at acute angles, said eccentricbeing mounted on said slide member and said slide member being drivinglyconnected to said sleeve so that said eccentric is rotated by saiddriving means around said axis; a bifurcated member having a pair ofarms extending along opposite sides of said slide member within saidsleeve; a rod supported between said arms extending through and slidablyengaging the side walls of said cam slot; adjusting means attached tosaid slide member and manually operable means for moving said adjustingmeans axially with respect to said bearing structure, thereby effectingmovement of said bifurcated member axially of said sleeve andtherebymoving said eccentric radially with respect to said sleeve.

7. Mechanism for adjustably supporting the throw of an eccentric withrespect to an axis and arranged for adjustment of said throw while saideccentric is rotating around said axis and for holding same in adjustedposition after said adjustment is effected, comprising in combination:bearing structure and means for supporting same; a cylindrical sleeveconcentric with said axis and supported within said bearing structurefor rotation around said axis, a pair of spaced parallel rods mountedupon and extending diametrically within said sleeve; driving means forrotating said sleeve; a slide member slidably supported upon said rodsand located within said sleeve for movement radially with respectthereto, said slide member having a radially angular cam surfacethereon, said eccentric being mounted upon said slide member and saidslide member being drivingly connected to said sleeve so that saideccentric is rotated by said driving means around said axis; a reactionmember extending along said slide member within said sleeve andsupporting means slidably engaging the cam surface; adjusting meansattached to said reaction member and manually operable means for movingsaid adjusting means axially with respect to said bearing structure,thereby effecting movement of said reatcion member axially of saidsleeve and thereby moving said eccentric radially with respect to saidsleeve.

8. A grinding machine, particularly for grinding tools, comprising incombination: a support frame; a bracket pivotally supported near itslower end upon said frame for oscillation with respect thereto about afirst axis; a grinding wheel; a shaft for supporting said grinding wheeland means rotatably supporting said shaft on said bracket near the upperend thereof, the axis of said shaft being parallel to said first axis;drive means mounted upon said frame below said first axis in substantialvertical alignment with said first axis and said shaft; means connectingsaid drive means to said shaft for constantly rotating said shaft, saiddrive means being partially supported on said shaft by said connectingmeans; eccentric means including a driven member rotatably supportedupon said frame, a driving member eccentrically mounted upon said drivenmember and means for adjusting the eccentricity of said driven memberwith respect to said driving member; a lever pivotally mounted betweenits ends upon said frame, one end of said lever having a slot into whichsaid driven member is operably received; an adjustable pitman connectedto the other end of said lever and to said bracket at a point spacedfrom the said first axis; whereby rotary movement of said eccentricmeans results in oscillatory movement of said bracket so that an axialface of said grinding wheel is oscillated in a plane perpendicular tothe axis of said rotatable shaft; and a work support adjustably mountedonsaid frame.

9. The structure of claim 7 wherein said cam surface is provided by thewall means defining a slot extending through said slide member, saidwall means being substantially perpendicular to a plane defined by thelengthwise axes of said parallel rods, and wherein said means slidablyengaging the cam surface is an element extending into said slot andrigidly secured to said reaction member.

References Cited in the file of this patent UNITED STATES PATENTS2,471,443 Munro May 31, 1949 2,544,604 Mader Mar. 6, 1951

